FIG. 1 depicts a schematic diagram of a portion of a wireless telecommunications system in the prior art, which system provides wireless telecommunications service to a number of wireless terminals (e.g., wireless terminals 101-1 through 101-3) that are situated within a geographic region. The heart of a typical wireless telecommunications system is a wireless switching center ("WSC"), which also may be known as a mobile switching center or mobile telephone switching office. Typically, a wireless switching center (e.g., WSC 120) is connected to a plurality of base stations (e.g., base stations 103-1 through 103-5) that are dispersed throughout the geographic region serviced by the system and to the local and long-distance telephone and data networks (e.g., local-office 130, local-office 138 and toll-office 140). A wireless switching center is responsible for, among other things, establishing and maintaining a call between a first wireless terminal and a second wireless terminal or, alternatively, between a wireless terminal and a wireline terminal (e.g., wireline terminal 150), which is connected to the system via the local and/or long-distance networks.
The geographic region serviced by a wireless telecommunications system is partitioned into a number of spatially distinct areas called "cells." As depicted in FIG. 1, each cell is schematically represented by a hexagon. In practice, however, each cell has an irregular shape that depends on the topography of the terrain surrounding the cell. Typically, each cell contains a base station, which comprises: (1) the radios and antennas that the base station uses to communicate with wireless terminals in that cell; and (2) the transmission equipment that the base station uses to communicate with the wireless switching center.
For example, when a user of wireless terminal 101-1 desires to transmit information to a user of wireless terminal 101-2, wireless terminal 101-1 transmits a packet bearing the user's information to base station 103-1. The packet is then relayed by base station 103-1 to wireless switching center 120 via wireline 102-1. Because wireless terminal 101-2 is in the cell serviced by base station 103-1, wireless switching center 120 returns the packet back to base station 103-1, which relays it to wireless terminal 101-2.
The demand for wireless service is never uniform throughout a geographic region. For example, the demand for service is likely to be greater in urban areas and along highways than in wilderness areas. Furthermore, the demand for wireless service in any area changes with the time of day, the day of the week, the seasons of the year, and other factors. For example, a parade or football game or traffic jam can corral a large number of people with wireless terminals into a small area, which temporarily increases the demand in that area.
In practice, the base stations in a wireless telecommunications system are traditionally positioned throughout a geographic region without consideration for where in that region the demand for wireless service will be heaviest or lightest. Instead, base stations are typically positioned uniformly throughout a geographic region (e.g., one base station every 5 miles) in such a manner that each base station services an area of approximately equal size. This implies that some base stations will be underutilized while others are heavily utilized and possibly overwhelmed.
In other words, because the base stations are fixed and uniformly dispersed, but the demand for service is not, there will typically be a mismatch between where the base stations exist and where they are needed. This causes the owner of the wireless telecommunications system to lose money in two ways. First, if the demand for service in an area is not met, then the owner cannot charge for service that is not provided. Second, the owner must spend considerable sums of money on base stations that are underutilized.
One solution is to position more base stations in those areas in which the demand for service is expected to be higher (e.g., at a football stadium). But if the demand for service varies with time in those areas, the base stations in those areas will spend a considerable percentage of the time underutilized. This, as stated above, costs the owner of the wireless telecommunications system to lose money.
Therefore, the need exists for a wireless telecommunications system in which the demand for wireless service is more closely matched by the presence of facilities to meet that demand, even when the demand for service varies with time.